OpenTelemetry Node
This module provides automated instrumentation and tracing for Node.js applications.
For manual instrumentation see the
@opentelemetry/tracing package.
How does automated instrumentation work?
This package exposes a NodeTracer
that will automatically hook into the module loader of Node.js.
For this to work, please make sure that NodeTracer
is initialized before any other module of your application, (like http
or express
) is loaded.
OpenTelemetry comes with a growing number of instrumentation plugins for well know modules (see supported modules) and an API to create custom plugins (see the plugin developer guide).
Whenever a module is loaded NodeTracer
will check if a matching instrumentation plugin has been installed.
Please note: This module does not bundle any plugins. They need to be installed separately.
If the respective plugin was found, it will be used to patch the original module to add instrumentation code.
This is done by wrapping all tracing-relevant functions.
This instrumentation code will automatically
- extract a trace-context identifier from inbound requests to allow distributed tracing (if applicable)
- make sure that this current trace-context is propagated while the transaction traverses an application (see @opentelemetry/opentelemetry-scope-base for an in-depth explanation)
- add this trace-context identifier to outbound requests to allow continuing the distributed trace on the next hop (if applicable)
- create and end spans
In short, this means that this module will use provided plugins to automatically instrument your application to produce spans and provide end-to-end tracing by just adding a few lines of code.
Creating custom spans on top of auto-instrumentation
Additionally to automated instrumentation, NodeTracer
exposes the same API as @opentelemetry/tracing, allowing creating custom spans if needed.
Installation
npm install --save @opentelemetry/core
npm install --save @opentelemetry/node
npm install --save @opentelemetry/plugin-http
npm install --save @opentelemetry/plugin-grpc
npm install --save @opentelemetry/plugin-https
Usage
The following code will configure the NodeTracer
to instrument http
using @opentelemetry/plugin-http
.
const opentelemetry = require('@opentelemetry/core');
const { NodeTracer } = require('@opentelemetry/node');
const tracer = new NodeTracer({
plugins: {
http: {
enabled: true,
path: '@opentelemetry/plugin-http',
}
}
});
opentelemetry.initGlobalTracer(tracer);
const http = require('http');
To enable instrumentation for all supported modules, create an instance of NodeTracer
without providing any plugin configuration to the constructor.
const opentelemetry = require('@opentelemetry/core');
const { NodeTracer } = require('@opentelemetry/node');
const tracer = new NodeTracer();
opentelemetry.initGlobalTracer(tracer);
Examples
See how to automatically instrument http and gRPC using node-sdk.
Useful links
License
Apache 2.0 - See LICENSE for more information.